|Name||Mr. Iago Neira|
|Organization or Institution||University of Miami|
Thermodynamic and kinetic studies of CB7 binding of nicotinic acid-terminated-xylylene guests.
Iago Neira and Angel Kaifer.
Department of Chemistry, University of Miami, Coral Gables, Florida, 33124.
It is well-known that xylylene diamine is an excellent guest for binding by cucurbituril (CB7). In this work we have prepared two new compounds by reaction of xylylene dibromide with nicotinic acid and isonicotinic acid. The resulting guests have a dicationic central site flanked by pyridinium carboxylate groups. We have investigated the equilibrium association constants (K) between our two guests and CB7. We have also measured the rate constants for dissociation (koff) for these complexes and used these values to determine the rate constants for association (kon). While the K values are very similar for the two types of terminal groups, the rate constants were substantially faster in the case of nicotinic acid. We are currently trying to understand the origin of these kinetic differences.